#10083: ghc: panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: hedayaty | Owner: Type: bug | Status: infoneeded Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Comment (by simonpj): Actually comment:17 does '''not''' fix #10083, because I found that the fix made the compiler go slower: {{{ Unexpected stat failures: perf/compiler T1969 [stat not good enough] (normal) perf/compiler T9872a [stat not good enough] (normal) perf/compiler T9872b [stat not good enough] (normal) perf/compiler T9872c [stat not good enough] (normal) perf/compiler T9872d [stat not good enough] (normal) bytes allocated value is too high: Deviation T1969(normal) bytes allocated: 7.5 % Deviation T9872d(normal) bytes allocated: 9.3 % Deviation T9872c(normal) bytes allocated: 8.4 % }}} by about 8% allocation overall. So the patch has all the code, but the key bit is commented out. See `Note [Inlining and hs-boot files]` in `TcBinds`. Presumably disabling inlining of functions exported by a `hs-boot` file really kills GHC's performance somewhere, implausible though it sounds. I suppose the next thing to do is to find out why, but I just don't have time to do that now, so I'm parking the whole thing. Sigh. Does anyone want to help? -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10083#comment:18 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler